Video Adds New Dimension to Snapper Research
May 31, 2012
By DAVID RAINER
Alabama Department of Conservation and Natural Resources
Graduate student Kevin Gregalis deftly manipulated the switches on what many would mistake for a game controller to a Nintendo or Xbox. But this was no game. Gregalis was maneuvering a Remotely Operated Vehicle (ROV) with a camera tethered to the equipment aboard the Lady Ann charter boat.
As the ROV gently glided near the bottom in 85 feet of water, a familiar site soon popped up on the screen. A red snapper peered curiously at the approaching machine and then continued its foray into the depths in search of a meal. Snapper after snapper soon showed up on the screen as the ROV approached the target, one of the 100 obsolete battle tanks that was deployed off the Alabama coast in the mid 1990s as part of the Tanks to Reefs program.
Capt. Mike Thierry, who has been ferrying marine scientists and graduate students on these excursions out of Dauphin Island for the past 20 years, said you really don’t know “the rest of the story” until you put a camera down on a reef.
“One time today my fish finder was lit up with fish and we weren’t catching many,” Thierry said. “Then we dropped the camera down and sure enough they were there. You don’t know whether a school of baitfish had just come through or what. At some spots, they were as hungry as could be, so there may not have been any baitfish come by there in a while. There are so many variables that you can’t see. When you’ve got 10-12 people standing around on the dock, not all of us are hungry. But if we were starving to death, we’d all be fighting over something to eat.
“With the camera, you can tell they’re there. They may not bite, but they’re there. You’re not going to catch every fish off the reef. People say, ‘Oh yeah, you can clean off a reef,’ and I once thought the same thing. I don’t believe that’s true now at all. That’s what the camera showed us.”
With a 40-day red snapper season set to start on June 1, Dr. Bob Shipp, head of Marine Sciences at the University of South Alabama, and his graduate students want to see how the recreational snapper season impacts what are commonly referred to as “public” spots like the tanks.
“With the snapper season being so short and so many questions about the health of the snapper stocks and how accurate the stock assessments are, what we’re doing is sampling some of the artificial reefs off Alabama,” Shipp said. “These are public reefs. The numbers are published. Everybody knows them. They’re 12-14 miles offshore, which means easy access.
“We’re using video and regular hook and line to sample these reefs now before the season opens. When the season is over, we’ll come and sample them all again to see what kind of impact this very short season has. We’ll see if they’ve been cleaned off or whether they are in good shape and can stand a little more pressure.”
Shipp said that the trip on May 18 included a sampling of five tanks and an old barge, called the Buffalo Barge, near Gulf Shores. Shipp also said some of these tanks have been identified as possible sources of diseased fish after the Deepwater Horizon oil spill.
“We have been sampling these public reefs on a pretty regular basis, and we have not picked up a single incident of a fish with any kind of anomaly,” he said. “In addition to that, we put the camera down. It’s a very high-tech camera and we haven’t seen anything of concern. We probably caught 200 snapper today and we didn’t see any lesions or anything.”
Shipp said when the red snapper research began more than 20 years ago, a tagging study was done to determine whether red snapper moved from reef to reef or called one reef home, more or less. Current research is funded through the Alabama Marine Resources Division utilizing Sport Fish Restoration funds.
“It turns out snapper generally will stay at the same site or close to it, unless they are impacted by a major tropical storm,” he said. “Then they’ll disperse. That led to some other studies. We’ve had a number of graduate students who have gotten degrees doing this research. The current head of the Florida Fish and Wildlife Conservation Commission Division of Marine Fisheries Management is Jessica McCawley, one of our students. She did a master’s thesis on red snapper feeding habits.
“We’re doing a study now on how deep you can bring a snapper up, release him and have him survive. The prevailing theory was that, after you get deeper than 70 to 80 feet, they’re not going to survive. But we’ve got a half-dozen stations in 150 feet of water, and we’ve been tagging them for three or four years. We’ve recaptured a number of those fish. As long as the fish are vented (releasing gases from the swim bladder) and are not gut-hooked, they have a pretty high chance of survival.”
In conjunction with the red snapper research, Shipp and his cohorts have also been studying the gray triggerfish, which has recently come under additional restrictions by the National Marine Fisheries Service. A quota has been established for triggerfish, as well as an increase in the minimum size and the method of measurement. The old limit was measured by total length. The new regulations require that a triggerfish must be 14 inches measured by fork length. Shipp also expects the quota to be filled some time in June.
“What we’ve found on triggerfish is they are even more faithful to a site than snapper,” he said. “We’ve had one triggerfish that we’ve recaptured six times from the same site. I don’t think snapper stocks are in nearly the trouble that the stock assessment people say. But the triggerfish assessment I tend to agree with. All the indices of abundance are pointing down. All the National Marine Fisheries Service and the Gulf Council can do is increase restrictions. Triggerfish have a little trailer on their tail fin, so when you go from a total length to a fork length, you’re going to a lot, lot bigger fish. This is a significant size increase.”
Shipp said the recent outing in the Gulf to check the tanks provided additional confirmation of his theory that there is an abundance of red snapper off the Alabama coast.
“Our very well known artificial reefs are holding a tremendous amount of snapper,” he said. “We’ve got a lot of young snapper, and we’ve got a lot of large 12- to 14-pound snapper out there. You know there are between 10,000 and 20,000 reefs out there in our reef permit zones. Do the numbers. If each reef holds 500 to 1,000 pounds of snapper, imagine how many red snapper live off Alabama in our artificial reef zones. The reefs combined with the petroleum structures in the north central and northwestern Gulf is where 70 percent of snapper are landed now, both recreationally and commercially. These snapper come from areas that produced practically no snapper at all historically. In the 1940s when the oil rigs started going in, and then in the 1950s and 60s when Alabama started its reef program, the demographics of red snapper changed dramatically.”
Shipp said the use of the high-definition camera on the ROV has added another dimension to and increased his confidence in their fisheries research.
“For example, when you fish these reefs, everything you catch is snapper with a few triggerfish and an occasional vermilion snapper,” he said. “You put the camera down and see a whole different assemblage. You see gray snapper, sheepshead and other species you don’t capture. You get a skewed view when you base your assessment on hook-and-line. When you put the camera down, you see it’s quite different. And sometimes we’ll go to a spot and only catch a half-dozen fish and think the spot has been fished out. But, you put the camera down and the spot is loaded with fish. They’re just not biting. Who knows why. That’s what makes fishing fun.”
PHOTOS: (by David Rainer) Graduate student Trey Spearman tosses the ROV over the stern of the Lady Ann on a recent red snapper research trip by the University of South Alabama. The high definition camera captured video of red snapper and other fish swimming around five of the 100 battle tanks that were deployed off the Alabama coast in the 1990s as artificial reefs. During the trip, red snapper were weighed, measured and tagged as part of the research. Graduate student Erin Money shows how a gray triggerfish must be measured to comply with the new 14-inch minimum fork length under new National Marine Fisheries Service regulations.